Example usage for java.util Map computeIfAbsent

Introduction

In this page you can find the example usage for java.util Map computeIfAbsent.

Prototype

default V computeIfAbsent(K key, Function<? super K, ? extends V> mappingFunction) 

Source Link

Document

If the specified key is not already associated with a value (or is mapped to null ), attempts to compute its value using the given mapping function and enters it into this map unless null .

Usage

From source file:at.gridtec.lambda4j.function.bi.conversion.BiCharToIntFunction.java

/**
 * Returns a memoized (caching) version of this {@link BiCharToIntFunction}. Whenever it is called, the mapping
 * between the input parameters and the return value is preserved in a cache, making subsequent calls returning the
 * memoized value instead of computing the return value again.
 * <p>// w w  w. j  a  va  2 s. c o m
 * Unless the function and therefore the used cache will be garbage-collected, it will keep all memoized values
 * forever.
 *
 * @return A memoized (caching) version of this {@code BiCharToIntFunction}.
 * @implSpec This implementation does not allow the input parameters or return value to be {@code null} for the
 * resulting memoized function, as the cache used internally does not permit {@code null} keys or values.
 * @implNote The returned memoized function can be safely used concurrently from multiple threads which makes it
 * thread-safe.
 */
@Nonnull
default BiCharToIntFunction memoized() {
    if (isMemoized()) {
        return this;
    } else {
        final Map<Pair<Character, Character>, Integer> cache = new ConcurrentHashMap<>();
        final Object lock = new Object();
        return (BiCharToIntFunction & Memoized) (value1, value2) -> {
            final int returnValue;
            synchronized (lock) {
                returnValue = cache.computeIfAbsent(Pair.of(value1, value2),
                        key -> applyAsInt(key.getLeft(), key.getRight()));
            }
            return returnValue;
        };
    }
}

---

From source file:at.gridtec.lambda4j.function.bi.conversion.BiBooleanToFloatFunction.java

/**
 * Returns a memoized (caching) version of this {@link BiBooleanToFloatFunction}. Whenever it is called, the mapping
 * between the input parameters and the return value is preserved in a cache, making subsequent calls returning the
 * memoized value instead of computing the return value again.
 * <p>//  w  ww .  ja  v a 2  s  .c  om
 * Unless the function and therefore the used cache will be garbage-collected, it will keep all memoized values
 * forever.
 *
 * @return A memoized (caching) version of this {@code BiBooleanToFloatFunction}.
 * @implSpec This implementation does not allow the input parameters or return value to be {@code null} for the
 * resulting memoized function, as the cache used internally does not permit {@code null} keys or values.
 * @implNote The returned memoized function can be safely used concurrently from multiple threads which makes it
 * thread-safe.
 */
@Nonnull
default BiBooleanToFloatFunction memoized() {
    if (isMemoized()) {
        return this;
    } else {
        final Map<Pair<Boolean, Boolean>, Float> cache = new ConcurrentHashMap<>();
        final Object lock = new Object();
        return (BiBooleanToFloatFunction & Memoized) (value1, value2) -> {
            final float returnValue;
            synchronized (lock) {
                returnValue = cache.computeIfAbsent(Pair.of(value1, value2),
                        key -> applyAsFloat(key.getLeft(), key.getRight()));
            }
            return returnValue;
        };
    }
}

---

From source file:at.gridtec.lambda4j.function.bi.conversion.BiBooleanToShortFunction.java

/**
 * Returns a memoized (caching) version of this {@link BiBooleanToShortFunction}. Whenever it is called, the mapping
 * between the input parameters and the return value is preserved in a cache, making subsequent calls returning the
 * memoized value instead of computing the return value again.
 * <p>/*from w ww. ja v  a  2  s . c o  m*/
 * Unless the function and therefore the used cache will be garbage-collected, it will keep all memoized values
 * forever.
 *
 * @return A memoized (caching) version of this {@code BiBooleanToShortFunction}.
 * @implSpec This implementation does not allow the input parameters or return value to be {@code null} for the
 * resulting memoized function, as the cache used internally does not permit {@code null} keys or values.
 * @implNote The returned memoized function can be safely used concurrently from multiple threads which makes it
 * thread-safe.
 */
@Nonnull
default BiBooleanToShortFunction memoized() {
    if (isMemoized()) {
        return this;
    } else {
        final Map<Pair<Boolean, Boolean>, Short> cache = new ConcurrentHashMap<>();
        final Object lock = new Object();
        return (BiBooleanToShortFunction & Memoized) (value1, value2) -> {
            final short returnValue;
            synchronized (lock) {
                returnValue = cache.computeIfAbsent(Pair.of(value1, value2),
                        key -> applyAsShort(key.getLeft(), key.getRight()));
            }
            return returnValue;
        };
    }
}

---

From source file:at.gridtec.lambda4j.function.bi.conversion.BiDoubleToCharFunction.java

/**
 * Returns a memoized (caching) version of this {@link BiDoubleToCharFunction}. Whenever it is called, the mapping
 * between the input parameters and the return value is preserved in a cache, making subsequent calls returning the
 * memoized value instead of computing the return value again.
 * <p>// ww  w . j a v  a  2 s .c o m
 * Unless the function and therefore the used cache will be garbage-collected, it will keep all memoized values
 * forever.
 *
 * @return A memoized (caching) version of this {@code BiDoubleToCharFunction}.
 * @implSpec This implementation does not allow the input parameters or return value to be {@code null} for the
 * resulting memoized function, as the cache used internally does not permit {@code null} keys or values.
 * @implNote The returned memoized function can be safely used concurrently from multiple threads which makes it
 * thread-safe.
 */
@Nonnull
default BiDoubleToCharFunction memoized() {
    if (isMemoized()) {
        return this;
    } else {
        final Map<Pair<Double, Double>, Character> cache = new ConcurrentHashMap<>();
        final Object lock = new Object();
        return (BiDoubleToCharFunction & Memoized) (value1, value2) -> {
            final char returnValue;
            synchronized (lock) {
                returnValue = cache.computeIfAbsent(Pair.of(value1, value2),
                        key -> applyAsChar(key.getLeft(), key.getRight()));
            }
            return returnValue;
        };
    }
}

---

From source file:at.gridtec.lambda4j.function.bi.conversion.BiCharToFloatFunction.java

/**
 * Returns a memoized (caching) version of this {@link BiCharToFloatFunction}. Whenever it is called, the mapping
 * between the input parameters and the return value is preserved in a cache, making subsequent calls returning the
 * memoized value instead of computing the return value again.
 * <p>/*w  w w  .  j  ava  2 s .c om*/
 * Unless the function and therefore the used cache will be garbage-collected, it will keep all memoized values
 * forever.
 *
 * @return A memoized (caching) version of this {@code BiCharToFloatFunction}.
 * @implSpec This implementation does not allow the input parameters or return value to be {@code null} for the
 * resulting memoized function, as the cache used internally does not permit {@code null} keys or values.
 * @implNote The returned memoized function can be safely used concurrently from multiple threads which makes it
 * thread-safe.
 */
@Nonnull
default BiCharToFloatFunction memoized() {
    if (isMemoized()) {
        return this;
    } else {
        final Map<Pair<Character, Character>, Float> cache = new ConcurrentHashMap<>();
        final Object lock = new Object();
        return (BiCharToFloatFunction & Memoized) (value1, value2) -> {
            final float returnValue;
            synchronized (lock) {
                returnValue = cache.computeIfAbsent(Pair.of(value1, value2),
                        key -> applyAsFloat(key.getLeft(), key.getRight()));
            }
            return returnValue;
        };
    }
}

---

From source file:at.gridtec.lambda4j.function.bi.conversion.BiCharToShortFunction.java

/**
 * Returns a memoized (caching) version of this {@link BiCharToShortFunction}. Whenever it is called, the mapping
 * between the input parameters and the return value is preserved in a cache, making subsequent calls returning the
 * memoized value instead of computing the return value again.
 * <p>/*ww  w  .  ja va2 s.  c  o m*/
 * Unless the function and therefore the used cache will be garbage-collected, it will keep all memoized values
 * forever.
 *
 * @return A memoized (caching) version of this {@code BiCharToShortFunction}.
 * @implSpec This implementation does not allow the input parameters or return value to be {@code null} for the
 * resulting memoized function, as the cache used internally does not permit {@code null} keys or values.
 * @implNote The returned memoized function can be safely used concurrently from multiple threads which makes it
 * thread-safe.
 */
@Nonnull
default BiCharToShortFunction memoized() {
    if (isMemoized()) {
        return this;
    } else {
        final Map<Pair<Character, Character>, Short> cache = new ConcurrentHashMap<>();
        final Object lock = new Object();
        return (BiCharToShortFunction & Memoized) (value1, value2) -> {
            final short returnValue;
            synchronized (lock) {
                returnValue = cache.computeIfAbsent(Pair.of(value1, value2),
                        key -> applyAsShort(key.getLeft(), key.getRight()));
            }
            return returnValue;
        };
    }
}

---

From source file:at.gridtec.lambda4j.function.bi.conversion.BiIntToDoubleFunction.java

/**
 * Returns a memoized (caching) version of this {@link BiIntToDoubleFunction}. Whenever it is called, the mapping
 * between the input parameters and the return value is preserved in a cache, making subsequent calls returning the
 * memoized value instead of computing the return value again.
 * <p>/*from w w w  .  j  a va2  s  . c om*/
 * Unless the function and therefore the used cache will be garbage-collected, it will keep all memoized values
 * forever.
 *
 * @return A memoized (caching) version of this {@code BiIntToDoubleFunction}.
 * @implSpec This implementation does not allow the input parameters or return value to be {@code null} for the
 * resulting memoized function, as the cache used internally does not permit {@code null} keys or values.
 * @implNote The returned memoized function can be safely used concurrently from multiple threads which makes it
 * thread-safe.
 */
@Nonnull
default BiIntToDoubleFunction memoized() {
    if (isMemoized()) {
        return this;
    } else {
        final Map<Pair<Integer, Integer>, Double> cache = new ConcurrentHashMap<>();
        final Object lock = new Object();
        return (BiIntToDoubleFunction & Memoized) (value1, value2) -> {
            final double returnValue;
            synchronized (lock) {
                returnValue = cache.computeIfAbsent(Pair.of(value1, value2),
                        key -> applyAsDouble(key.getLeft(), key.getRight()));
            }
            return returnValue;
        };
    }
}

---

From source file:at.gridtec.lambda4j.function.bi.conversion.BiBooleanToCharFunction.java

/**
 * Returns a memoized (caching) version of this {@link BiBooleanToCharFunction}. Whenever it is called, the mapping
 * between the input parameters and the return value is preserved in a cache, making subsequent calls returning the
 * memoized value instead of computing the return value again.
 * <p>//from w  w  w .j a v  a  2s .c om
 * Unless the function and therefore the used cache will be garbage-collected, it will keep all memoized values
 * forever.
 *
 * @return A memoized (caching) version of this {@code BiBooleanToCharFunction}.
 * @implSpec This implementation does not allow the input parameters or return value to be {@code null} for the
 * resulting memoized function, as the cache used internally does not permit {@code null} keys or values.
 * @implNote The returned memoized function can be safely used concurrently from multiple threads which makes it
 * thread-safe.
 */
@Nonnull
default BiBooleanToCharFunction memoized() {
    if (isMemoized()) {
        return this;
    } else {
        final Map<Pair<Boolean, Boolean>, Character> cache = new ConcurrentHashMap<>();
        final Object lock = new Object();
        return (BiBooleanToCharFunction & Memoized) (value1, value2) -> {
            final char returnValue;
            synchronized (lock) {
                returnValue = cache.computeIfAbsent(Pair.of(value1, value2),
                        key -> applyAsChar(key.getLeft(), key.getRight()));
            }
            return returnValue;
        };
    }
}

---

From source file:at.gridtec.lambda4j.function.bi.conversion.BiBooleanToDoubleFunction.java

/**
 * Returns a memoized (caching) version of this {@link BiBooleanToDoubleFunction}. Whenever it is called, the
 * mapping between the input parameters and the return value is preserved in a cache, making subsequent calls
 * returning the memoized value instead of computing the return value again.
 * <p>//from ww  w . j a  v a 2 s.  co  m
 * Unless the function and therefore the used cache will be garbage-collected, it will keep all memoized values
 * forever.
 *
 * @return A memoized (caching) version of this {@code BiBooleanToDoubleFunction}.
 * @implSpec This implementation does not allow the input parameters or return value to be {@code null} for the
 * resulting memoized function, as the cache used internally does not permit {@code null} keys or values.
 * @implNote The returned memoized function can be safely used concurrently from multiple threads which makes it
 * thread-safe.
 */
@Nonnull
default BiBooleanToDoubleFunction memoized() {
    if (isMemoized()) {
        return this;
    } else {
        final Map<Pair<Boolean, Boolean>, Double> cache = new ConcurrentHashMap<>();
        final Object lock = new Object();
        return (BiBooleanToDoubleFunction & Memoized) (value1, value2) -> {
            final double returnValue;
            synchronized (lock) {
                returnValue = cache.computeIfAbsent(Pair.of(value1, value2),
                        key -> applyAsDouble(key.getLeft(), key.getRight()));
            }
            return returnValue;
        };
    }
}

---

From source file:at.gridtec.lambda4j.function.tri.obj.BiObjByteFunction.java

/**
 * Returns a memoized (caching) version of this {@link BiObjByteFunction}. Whenever it is called, the mapping
 * between the input parameters and the return value is preserved in a cache, making subsequent calls returning the
 * memoized value instead of computing the return value again.
 * <p>/*  www  .ja  v a2s  .  c om*/
 * Unless the function and therefore the used cache will be garbage-collected, it will keep all memoized values
 * forever.
 *
 * @return A memoized (caching) version of this {@code BiObjByteFunction}.
 * @implSpec This implementation does not allow the input parameters or return value to be {@code null} for the
 * resulting memoized function, as the cache used internally does not permit {@code null} keys or values.
 * @implNote The returned memoized function can be safely used concurrently from multiple threads which makes it
 * thread-safe.
 */
@Nonnull
default BiObjByteFunction<T, U, R> memoized() {
    if (isMemoized()) {
        return this;
    } else {
        final Map<Triple<T, U, Byte>, R> cache = new ConcurrentHashMap<>();
        final Object lock = new Object();
        return (BiObjByteFunction<T, U, R> & Memoized) (t, u, value) -> {
            final R returnValue;
            synchronized (lock) {
                returnValue = cache.computeIfAbsent(Triple.of(t, u, value),
                        key -> apply(key.getLeft(), key.getMiddle(), key.getRight()));
            }
            return returnValue;
        };
    }
}

---

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